Oscillator



March 8, 1938.

MAGET/c FIELD E. G. Ll NDER OSCILLATOR Filed Aug. 20, 1935 Patented Mar. 8, 1938 UNITED STATES OSCILLATOR Ernest G. Linder, Surf City, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application August 20, 1935, Serial No. 36,974

12 Claims.

My invention relates to oscillators. More specifically, my invention is a multiple magnetron, or a multiple electronic ultrahigh frequency oscillator. I

One of the objects of my invention is to arrange a number of magnetron oscillators within a common envelope.

Another object is to connect a number of magnetron or electronic oscillators to a single resonant circuit to increase the power, developed therein.

A further object is to connect a number of ultra high frequency oscillators across a number of nodal points in a resonant circuit.

5 Other objects will appear in the accompanying specification.

Ultra high frequency oscillations have been generated by magnetron and other types of electronic oscillators. Although it has been feasible to generate extremely high frequencies, it has not been practical to generate large amounts of oscillatory energy. An increase in size of the electronic tube elements increases their interelectrode capacity and decreases their oscillatory frequency. My invention overcomes these difficulties by connecting a number of ultrahigh frequency oscillators to a single tank orresonant circuit. o

In the accompanying figures, Figure I is a schematic diagram of one embodiment of my invention, I

Figure II is a detailed perspective illustration of one of the magnetron oscillators and its magnetic circuit, and

9 Figure III is a diagram and a perspective showing of a positive grid oscillator which may be used in my invention.

In Figure I, within evacuated envelope I are a plurality of high frequency oscillators'3. Each 40 of these oscillators consists of two anodes 5, 1 and a cathode 9. The cathodes may be filaments or the like and are energized in parallel or series by any suitable source of current which is not shown. A resonant loop circuit connects the 45 anodes 5 and 1. Each of the resonant circuits l l is coupled to a resonant tank circuit [3, across a nodal voltage point IS. The couplingbetween 3 and I3 is the common portion of the circuits. Instead of coupling directly as shown, the several 50 resonant circuits 3 may be spaced from the single tank circuit l3. In this case the positive connection, represented as I9, must be made directly to each of the several resonant circuits 3 at their mid-points. The coupling may be adjusted by 55 varying the length of the common portion. or the spacing between the two circuits. If the coupling is too loose, the transfer of energy is inefficient. If the coupling is too close, the currentsin the separate resonant circuits will react deleteriously on each other. The coupling is determined by the desired width of the transmitted band and the required efiiciency.

The tank circuit I3 is resonant to a whole number of half wave lengths. The dotted lines I! represent the oscillatory voltage along a section of the tank circuit 13, and the polarities indicated areinstantaneous values- Each of the resonant circuits H is symmetrically arrangedabout a nodal point in the tank circuit and each of the resonant circuits H is properly phased. At a nodal point a connection I9 is made to the parallel wires of the resonant tank circuit l3. An anode battery 2! has its negative terminal connected to the cathode 9 and its positive terminal to the center of the nodal connection l9, An

antenna 23 may be connected to the resonant tank circuit (3. v

If a magnetic fieldof suitable strength is applied to each magnetron in a position substantially parallel to their cathodes .9, the several magnetrons will generate oscillations. The frequency of each of these oscillations is determined by each of the several resonant circuits II and the equation v where x=wave length, 7c=a constantyand H=the magnetic field strength. Thus it will beseen that each separate oscillator is generating oscillations which may be adjusted to the same frequency. The several separate oscillations may be fed in the proper phaseinto the tank or resonant circuit I3.

The magnetic fields have been illustrated by circular broken lines labelled magnetic field in Figure I. The fields may be created by a single magnetic circuit having the required number of pole pieces. I prefer to use several separate fields or adjustable pole pieces to facilitate individual adjustment of the magnetrons. In Figure II a magnetic field structure of one type is shown. A magnetic core 3| is energized by a solenoid 33 which is connected through arheostat 35 to a battery 3?. The magnetic field is established be tween the pole pieces N and S. The field is substantially parallel to the filament 39 of the mag-, netron. The filament is energized by a battery 4! or any suitable powerusource. Adjacent the filament or cathode 39 are the anodes 43, 45. The anodes are preferablyshaped into a hollow half cathode is a grid 55.

cylindrical iorm whose central axis is substantially coaxial with the cathode. The anodes are connected by a link circuit 41 which is preferably resonant. A wire or rod 49 represents a section of the resonant tank circuit ll of Figure I. A fragmentary portion of the evacuated envelope which surrounds the magnetron has been shown to simplify the illustration. The anode battery has been omitted. 1

Although I have illustrated the oscillators as magnetrons, any ultrahigh frequency generator;

may be employed. In Figure III a positive grid is h wn with the evacuated enveloh.

in fragmentary form. A suitable cathode 5iis energized by a battery 53. Surrounding the The anodes 51-59 are positioned around the grid and cathode. are joined by a resonantjcircuit'tl. The resonant circuit is coupled to the tank circuit 63.

This circuit is similar to the resonant tanlr circult lat: Figure I. A bridging circuit 65 is connectedtofnodal points on the tank circuit;

The center of the nodal connection 65 is joined to a biasing battery 61. lThis battery biases 'the anodes {either slightly positive or negative with respect to the cathode 5| The grid 55 is connected to the positive terminal of a battery '69 and the negative tenninal'of this battery is connected to the nodal, connection 65. The ultra high fi'requency positive grid oscillator is well known to those skilled in the art. This oscillator,jper se, is not my, invention, and a detailed description of 'thetheory' of operation is not re-,

quired. Itshouldbe understoodthat the oscillator of Figure In doesnot require a magnetic field. Theelements of the positive grid or the magnetron oscillator,:or;both, may be used as the separategener'atdrsofoscillatlons shown in Figure I. I prefer to'have separate means for adjusting the several biases of: the. separate positive grid oscillators. q

Vari ousm odifications may be made in my inventionjwithout departing from the spiritand scope thereof, and I desire, therefore, that only such limitations shall be placed thereon as are necessitated by thev prior art and set forthin the apbendedclaims I'claim: '1" p v v 1. In an oscillatory system, a plurality of magnetron oscillators, a plurality of magnetic fields for said oscillators, a separate resonant circuit oonnected-to'each of said magnetrons,-a single resonantcircuit having a' plurality ofi'nodal points, and means coupling each of said separate resonant. circuits across separate nodal points on said single. resonant circuit. 2. In j'a device :of the character described in claim 1, means for separately adjusting several of saidplu-ralityof-magnetic fields. 1

3. In: a device of the character described in claim'1,.an 'anten-na,-iand-means coupling said antenna to saidsingle resonant circuit.

tors of'said plurality ofv oscillators, a single resonantTcircuithavingi a numberof nodal points,

and means "coupling said separate resonant cit-' cults across. separate nodal points on said resonant/circuit. 1 A

5. In a device 'oi'hthe'character described in 7 claim 4, anumberof sources of voltage for biasingior each of said positive grid oscillators and means-for varying said-biases. a r

The anodes 6. In a device of the character described in claim 4, a single evacuated envelope enclosing said plurality of positive grid oscillators.

'7. In an oscillatory system, a plurality of magnetron oscillators, means for creating a magnetic field for said oscillators, a separate resonant cir- V cult connected to each of said magnetrons, a single resonant circuit having aplurality oi' nodal points, and means coupling each of said separate resonant circuits across single nodal points on said single resonant circuit.

8. In an oscillatory system a plurality of elec- *mme oscillation generators, said generators each including a single electronic oscillator and means for -imparting an oscillatory movement to the electronscreatingsaid oscillations; a plurality of circuits each connected to said generators and resonant to said oscillations; a single circuit resonant to a; frequency which is a multiple oi the resonant frequency of each of said plurality of circuits and further characterized by its adaptability for' theest'ablishment therein of standing waves ofo'pposite phases including voltage nodal and antinodal points; means for mutual coupling each of said plurality of circuits to'said single circuit in a serial arrayfwhereby each said mutual coupling includes in said single circuit portionsof voltage waves of" opposite phase and a single voltage nodal point and whereby each said generator impresses oscillationson'said single circuit in phasal' relations which create said standingwaves, and a single evacuated envelope for enclosing said plurality of'generators and resonant circuits. t i

9. In an oscillatory system a plurality of electronic oscillationgenerators, saidgenerators each including'a singleelectronicoscillator and means for imparting an oscillatory movement to the electrons creating said oscillations; a plurality of circuits each connected'to said generators and resonant to said oscillations; a single circuit resonanttoa-whole number of half wave lengths correspondingto the resonant frequency of each of s'aid'plurality of circuits and further charac-' terized by its-adaptabilityfor the establishment therein-of standing waves of opposite phases in,- cluding voltage -nodal' and antinodal points; means, i'or mutual coupling each of said plurality 'of circuits tosaid single circuit in a serial array, whereby each said mutual coupling includes in said single circuit portions of voltage waves of opposite phase and a single voltage nodal point-and whereby each said generator impresses oscillations on said single circuit in phasal relations which create said standing waves, and

,a single evacuated envelope for enclosing said plurality of generators and resonant circuits.

10. In an oscillatory system, a plurality of electronic oscillators including a single electronic oscillator and means for imparting oscillatory movements to the .electrons in each of said oscillators whereby oscillations of substantially the same oscillatory frequency are created; a plurality 'ofresonant'circuits respectively connected to said plurality of oscillators; a sing1e circuit resonant to a multiple of'said oscillatory frequency and characterized byhaving a length adaptable standing waves in said single circuit; and an evacuated envelope including said plurality of generators and said circuits.

11. In an oscillatory system, a plurality of magnetron oscillators, a plurality of magnetic fields for said oscillators, means for imparting oscillatory movements to the electrons in said oscillators, a separate circuit resonant to the period of said oscillatory movements and connected to each of said magnetrons, a single resonant circuit having a plurality of nodal points, and means coupling each of said separate resonant circuits across separate nodal points on said single resonant circuit.

12. In an oscillatory system, a plurality of magnetron oscillators, a plurality of magnetic fields for said oscillators, means for imparting oscillatory movements to the electrons in said oscillators, a separate circuit resonant to the period of said oscillatory movements and connected to each of said magnetrons, a single circuit resonant to a multiple number of half wave lengths corresponding to said oscillatory movements and having a plurality of nodal points, and means coupling each of said separate resonant circuits across separate nodal points on said single resonant circuit.

ERNEST G. LINDER. 

